Accurate 2-D DoA Estimation Based on Active Metasurface With Nonuniformly Periodic Time Modulation

Xia, Dexiao; Wang, Xin; Han, Jiaqi; Xue, Hao; Shi, Yan; Li, Long; Cui, Tiejun

doi:10.1109/tmtt.2022.3222322

Cited by 17 publications

(13 citation statements)

References 43 publications

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“…1 , metasurfaces are capable of performing a wide range of functions that are critical for future wireless communication systems. These functions include surface-assisted communication enhancement, [ 6 , 9–11 ], nonreciprocal wave transmission and reflection [ 12 , 23 ], beamsteering [ 24 ], signal-wave amplification [ 13 , 25 , 26 ], intelligent signal management and power handling [ 14 ], frequency conversion [ 15 , 27–29 ], analogue and digital signal modulation [ 18 , 30 ], signal processing, and direction of arrival estimation [ 31 ]. Metasurfaces offer several advantages over traditional components, such as being multi-functional, highly efficient, intelligent and compact.…”

Section: Metasurface-based Communication Schemesmentioning

confidence: 99%

Metasurfaces: physics and applications in wireless communications

Ataloglou

Taravati

Eleftheriades

2023

National Science Review

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The ever increasing number of wireless devices and systems has led to a crowded spectrum and increased the demand for versatile and multi-functional wireless apparatuses. Recently, metasurfaces are explored as a prominent technological solution to the current paradigm of spectrum scarcity by opportunistically sharing the spectrum with various users. In general, metasurfaces are passive/dynamic, ultra-compact, multi-functional and programmable structures which are capable of both reciprocal and nonreciprocal signal wave transmissions. The controllability and programmability of such metasurfaces are governed through DC bias and occasionally a radio-frequency (RF) modulation applied to the active components of the unit cells of the metasurface, e.g., diodes and transistors. This article overviews some of the recently proposed passive and dynamic metasurfaces and shows that metasurfaces can enhance the performance of wireless communications systems thanks to their unique physical features such as real-time signal coding, nonreciprocal-beam radiation, nonreciprocal beamsteering amplification, and advanced pattern-coding multiple access communication.

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Section: Metasurface-based Communication Schemesmentioning

confidence: 99%

Metasurfaces: physics and applications in wireless communications

Ataloglou

Taravati

Eleftheriades

2023

National Science Review

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“…This concept has resonated through the fields of wave physics and communications, leading to a range of exciting applications. [ 36 ] These include beam steering and shaping, [ 35,37,38 ] harmonic manipulations, [ 22,35,37 ] scattering‐signature control, [ 35 ] breaking reciprocity, [ 39,40 ] analog signal processing, [ 41 ] multiplexed wireless communications, [ 42,43 ] radar waveform generation, [ 44 ] EM sensing, [ 45,46 ] and the development of universal meta‐antennas. [ 47,48 ] Moreover, the idea of “asynchronous” STC metasurfaces, [ 49,50 ] which evolved from the principles of frequency diverse arrays [ 51,52 ] and frequency‐gradient metasurfaces, [ 53 ] was introduced to enable time‐dependent wavefront control.…”

Section: Introductionmentioning

confidence: 99%

Co‐Prime Modulation for Space‐Time‐Coding Digital Metasurfaces with Ultralow‐Scattering Characteristics

Zhang,

Huang,

Chen

et al. 2024

Adv Funct Materials

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Multi‐dimensional modulation of electromagnetic (EM) waves is critical in various fields such as electronic and photonic systems. Space‐time‐coding (STC) digital metasurfaces, an innovative platform for programmable metasurfaces, offer a straightforward and robust solution for spatio‐temporal modulation, thereby enabling EM‐wave manipulations in both space and frequency. Conventional STC schemes rely on periodic temporal modulations that are uniform in space (i.e., with same modulation frequency in all metasurface elements), and therefore do not take advantage of spatio‐temporal coupling effects that can be induced by non‐uniform periodic modulations (i.e., with different modulation frequencies across the metasurface elements). Here, a novel approach involving non‐uniform spatio‐temporal modulation, alongside co‐prime modulation, is introduced. This approach enhances the fundamental principles of STC digital metasurfaces and facilitates the synthesis of angular scattering responses across different frequencies, guided by harmonic coupling conditions. The proposed strategy results in a more even distribution of the scattered intensity in both space and frequency. For validation, an experimental proof‐of‐principle for spatial‐spectral diffuse scattering is presented. The experimental outcomes align closely with theoretical predictions, underscoring the effectiveness of co‐prime modulation in achieving ultralow‐scattering characteristics in STC digital metasurfaces. Moreover, this technique holds promise for applications in secure wireless communications, radar jamming, and complex beamforming.

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“…A variety of theories and functional designs have been explored based on this concept. [24][25][26][27][28][29][30][31][32][33][34] Explicitly, most research has been devoted to achieving precise control over EM waves in half-space, particularly regarding regulating the reflection or transmission of these waves. Indeed, the development of multifunctional metasurfaces capable of modulating the full-space EM waves holds significant promise for numerous applications across various fields.…”

Section: Introductionmentioning

confidence: 99%

Reconfigurable Transmission‐Reflection‐Integrated Coding Metasurface for Full‐Space Electromagnetic Wavefront Manipulation

Yin

Ren

Zhang

et al. 2023

Advanced Optical Materials

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Reconfigurable metasurfaces exhibit the capability of flexibly controlling electromagnetic (EM) waves, and the real‐time manipulation of tailored EM wavefront in full‐space is one of the steadily increasing interests. This paper proposes a reconfigurable transmission‐reflection‐integrated (TRI) coding metasurface, combining the functionalities of reconfigurable transmission and reflection metasurfaces. The meta‐particle is composed of a multilayer structure integrated with three positive‐intrinsic‐negative (PIN) diodes. By dynamically controlling the states of these diodes with the direct‐current (DC) bias voltage from a field‐programmable‐gate‐array (FPGA), meta‐particles achieve switching between transmission mode and reflection mode and independently modulate phase response. Metasurfaces can manipulate the reflected and transmitted wavefront by array encoding, allowing for full‐space control of the EM wavefront. Additionally, this paper demonstrates various functions implemented on this metasurface, including mode switching, beam scanning, shaping, focusing, and spatial scattering. As a proof of concept, a metasurface array prototype is fabricated and experimented. The simulation and measurement results agree well, confirming the effective ability of reconfigurable TRI metasurfaces to manipulate EM waves throughout full‐space. The proposed reconfigurable TRI coding metasurface opens the door for flexible wavefront control in the full‐space domain, with broad application prospects in areas such as microwave imaging, EM stealth, and smart radomes.

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Accurate 2-D DoA Estimation Based on Active Metasurface With Nonuniformly Periodic Time Modulation

Cited by 17 publications

References 43 publications

Metasurfaces: physics and applications in wireless communications

Metasurfaces: physics and applications in wireless communications

Co‐Prime Modulation for Space‐Time‐Coding Digital Metasurfaces with Ultralow‐Scattering Characteristics

Reconfigurable Transmission‐Reflection‐Integrated Coding Metasurface for Full‐Space Electromagnetic Wavefront Manipulation

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